Update TestDanglingEnds to O(n) speed

The elements don't care which they connect to, so don't search for
points on the page, just collect them all and then test them all

Adjusts f3dd5b73

eeschema/sch_commit.cpp

@@ -305,12 +305,6 @@ void SCH_COMMIT::pushSchEdit( const wxString& aMessage, int aCommitFlags )
         schItem->ClearEditFlags();
     }
 
-    if( frame )
-    {
-        frame->RecalculateConnections( this, NO_CLEANUP );
-        frame->TestDanglingEnds();
-    }
-
     if( schematic )
     {
         if( bulkAddedItems.size() > 0 )
@@ -326,7 +320,10 @@ void SCH_COMMIT::pushSchEdit( const wxString& aMessage, int aCommitFlags )
     if( !( aCommitFlags & SKIP_UNDO ) )
     {
         if( frame )
+        {
             frame->SaveCopyInUndoList( undoList, UNDO_REDO::UNSPECIFIED, false, dirtyConnectivity );
+            frame->RecalculateConnections( this, NO_CLEANUP );
+        }
     }
 
     m_toolMgr->PostEvent( { TC_MESSAGE, TA_MODEL_CHANGE, AS_GLOBAL } );
@@ -528,7 +525,6 @@ void SCH_COMMIT::Revert()
     if( frame )
     {
         frame->RecalculateConnections( nullptr, NO_CLEANUP );
-        frame->TestDanglingEnds();
     }
 
     clear();